Design Decisions and Exceptions

2013PDFBriefFHWA-SA-13-013Crash modification factorsTraffic safetyDesign methodsUnited StatesUnited States. Federal Highway Administration. Office of SafetyUnited States. Federal Highway Administration. Office of SafetyScurry, KarenFederal Highway AdministrationThe Crash Modification Factors (CMFs) in Practice: Using CMFs to Quantify the Safety Performance of Design Decisions and Exceptions guide describes and illustrates several opportunities to incorporate the latest methods to quantify safety in the design process using CMFs. The target audience includes those who are responsible for developing, reviewing, and approving designs and design exceptions. The purpose of this guide is to help raise awareness of opportunities to consider and quantify the safety impacts of design decisions, with a specific focus on the application of CMFs to support the design process. The objectives are to 1) identify opportunities to consider safety in the various steps of the design process, 2) describe various methods available for quantifying safety using CMFs, and 3) explain when it would be appropriate to employ each method. By providing safety awareness, designers will be better prepared to assess the safety impacts of individual design elements and evaluate the overall impact of design exceptions on the safety performance of a facility.93